有效寿命

This paper presents a new algorithm to calculate control parameters for west-east station keeping for dual-spin geostationary satellites.With the same accuracy provided by traditional ways,it is simpler and easier to understand.Also,the relationship between orbit control efficiency,rotation speed and width of engine impulse is explored.

0引言地球同步自旋卫星由于其技术成熟、运行稳定，在航天领域保持着强大的生命力，尤其是在气象卫星的运用上，它的自旋特性可大大降低有效载荷的复杂性并相应延长其寿命，因此我国在轨的风云二号气象卫星和欧洲2002年发射的第二代气象卫星都采用自旋平台。

Because the specific impulse of electric propulsion is ten times more than the chemistry propulsion, it appears very important in the application of satellite attitude control and station keeping, aerocraft deep space exploring and interstellar travelling. It can increase the payload and extend life, decrease the passive weight.

由于电推进的比冲比化学推进比冲高出一个数量级，因而在卫星姿态控制、位置保持以及空间飞行器深空探索、星际航行的应用中有重要意义，它或可以提高有效载荷、延长寿命，或可以降低消极质量。

But that's not all -- green roofs are a great way to handle water management in urban areas with overwhelmed sewerage systems (green roofs soak up excess precipitation), provide sanctuaries for urban wildlife, and actually extend the life span of the roof itself.

但还远不止这些优点——绿色屋顶以其强大的排水系统，能有效管理城市排水问题（绿色屋顶吸收大量突然降水）。绿色屋顶为城市种的野生动物提供避难所，同时也延长了屋顶绿化本身的寿命。

As a result of this section of the motor cutter, external oil pump, so as to effectively ensure the cutter of this subsection good ventilation cooling conditions, operational safety, long life.

由于本款裁断机的电机、油泵外置，从而有效保证了本款裁断机通风冷却条件好，运行安全，寿命长。

Especially how to make the best of resistance drop, reduce the erosion in grounding devices and prolong grounding devices' use is researched.

特别是如何有效地发挥降阻剂的降阻效果，减少其对接地装置地腐蚀，延长接地装置的使用寿命，进行了研究。

The marine growth is removed when the ship is out of the dock in order to prolong docking repair time and life of ship.

在船舶不进坞的情况下，有效地清除附在其外表面上的海生物，有利于延长船舶坞修时间和提高船舶使用寿命。

With the first generation of reconnaissance satellites in China, China's second-generation spy satellite orbital lifetime, satellite photos of the resolution, film-chip installed, and the effective utilization of film has been a significant increase.

与第一代中国侦察卫星相比，中国第二代侦察卫星的轨道寿命、卫星照片的分辨率、胶片的装片量，以及胶片的有效利用率都有大幅度增加。

The absorption properties of Nd:YVO4 crystals with various doping levels and lengths are reported.The 1 064 nm laser properties are compared,and the effective stimulated emission crosssections of different doping levels are calculated with upper-level life-times we have measured.Our investigation give a good advice for the optimization of LD end-pumped Nd:YVO4 laser.

对多种掺杂浓度、长度的Nd：YVO4晶体进行了吸收性质、激光性质的研究和对比，根据实验结果和测得的上能级寿命计算了不同掺杂浓度Nd：YVO4晶体的有效受激发射截面，对激光二极管端面泵浦Nd：YVO4固体激光器的最优化有实际指导意义。

The results show that it can effectively control the penetration of cobalt and improve the quality of diamond coating and improve tool's life by 10 times when the substrate is pretreated in the condition of acid leaching in dilute HCl for 15 min and then soaking in dilute ammonia solution for 10 min.

结果表明，在1∶3的稀盐酸中酸洗15 min后用氨水浸泡10 min的基片处理方法能有效地抑制金属钴的溢出，从而提高金刚石涂层的质量，并且使刀具使用寿命提高10倍以上。

I will endeavour to find you some assistance.

我尽力帮你找人帮忙。

At first I only know bruck is the idol of American younglings, afterwards I returned back to Taiwan ,even in Beijing last year ,I saw her poster everywhere, I was so surprised at her charm.

起初我只晓得布鲁克雷德丝是美国少男少女崇拜的偶像，后来回台湾，甚至去年在北京，居然也四处看见她的海报，才惊讶她的魅力之大。